NOTE: Maintenance includes any work required to
keep highways in usable condition that does not extend the service life of
the roadway beyond the original design. Restoration includes renovation.
Although the following categories are not generally considered maintenance,
they are included for comparison: Major Widening, Relocation, New Route.

SOURCE: U.S. Department of Transportation,
Federal Highway Administration, Highway
Statistics 2001, (Washington, DC),
"Miles of Federal-Aid Roadway Projects Underway by Improvement
Type" chart, available at http://www.fhwa.dot.gov/ohim, as of June 2003.